BAGHDAD – BAGHDAD (AP) — An agreement to form an alliance between Iranian-backed Shiite blocs gives the final say on political disputes to Iraq's top clerics, solidifying a role for the Shiite religious leadership in the country's likely new government.

The agreement, obtained by The Associated Press Wednesday, is likely to alienate Iraq's other religious and ethnic sects from the potential new government — especially minority Sunnis already wary of the Shiite-dominated leadership. The U.S. has warned against excluding Sunnis for fear that sidelining the Sunni-backed election winner could enflame tensions.

Several high-ranking Shiite officials confirmed to the AP the contents of the agreement, which lays out a list of conditions making possible the alliance between Prime Minister Nouri al-Maliki's State of Law coalition and the Iraqi National Alliance — until recently wary rivals for power.

But it is the referee role given to the nation's Shiite clergy, which holds enormous weight with the Shiite majority, that is the most contentious clause to Iraq's other political groups.

"The marjaiyah has the final say in solving all the disputes between the two sides and its directives and guidance are binding," the agreement said, referring to the religious Shiite leadership based in the holy city of Najaf.

The need to bring in the highest religious authorities of Iraq's Shiites is a reflection of the deep distrust between the two rival blocs, but it would also give a government formed by the coalition an overtly religious character.

Neighboring Iran, a Shiite theocracy where clerics have the final word on all matters of state, carries great influence with both groups and has long pushed for such an alliance.

The provision only applies to the alliance, not officially to any new government. But if the Shiite alliance dominates the next government, clerics would potentially have a direct say in policy.

The merger also means that the top vote-getter in the election, secular Shiite Ayad Allawi's Iraqiya list, which received strong Sunni backing, will be squeezed out of the process — angering his supporters.

Besides the Sunnis, the agreement might also alienate Kurds and other factions, making it difficult to form an inclusive government for the fragmented country.

"The fact that there is an official role for the clerical establishment is going to create a major problem," said Marina Ottaway, director of the Middle East program at the Washington-based Carnegie Endowment for International Peace. "This is an agreement that risks making Sunnis and Kurds second-class citizens."

Ahmed Chalabi, a prominent Shiite politician whose faulty intelligence was used by Washington to help justify the U.S.-led invasion, was one of the officials who signed the 11-point agreement.

He played down any idea that this would amount to a religious stamp on government decisions, partly, he said, because the clerical leadership has already indicated their reluctance to play a big role in Iraqi politics.

"It is an example of the level of respect that all these political parties and groups have for the marjaiyah," he said. "The marjaiyah doesn't want to get involved in this."

Chalabi said Iraq's other political groups should be reassured by the fact that Grand Ayatollah Ali al-Sistani — the revered Shiite cleric in Iraq who is essentially the head of the marjaiyah — has said no political groups should be excluded from the political process.

Together the new Shiite alliance will have 159 seats, just four shy of the majority needed in the 325-member parliament to form a government.

In an interview Wednesday, before the details of the agreement were revealed, U.S. Ambassador Christopher Hill maintained that "Sunnis have to be a part of the political process."

"You cannot run Iraq without having significant Sunni participation," he told the AP.

The dominant group under former leader Saddam Hussein, Iraq's Sunni Arabs have had little power since the 2003 U.S.-led invasion ushered in a succession of Shiite- and Kurdish-dominated governments.

For years, Sunnis swelled the ranks of a powerful insurgency that threw the country into turmoil, and the fear is that alienating them from the political process now could start the fighting anew.

Abdul-Ilah Kazim, a Sunni lawmaker with the Iraqiya list, rejected the political influence of the Shiite clerics in the new alliance. "There is a sectarian flavor to this one-sect agreement from start to finish and certainly all the world and Iraqi people will get its message," he said.

The Kurdish bloc, which holds 43 seats in parliament, has — at least publicly — been cautious about joining the Shiite coalition, citing the need for a broader government.

"As a Kurdish coalition, we are leaning toward forming a national unity government that includes all the main four winning blocs," said Fadhil Miran, an aide to Kurdish President Massoud Barzani. "We do not want a sectarian government, and we do not want the Iraqiya list to be excluded."

Al-Sistani is the most revered religious figure among Shiites in Iraq — and many abroad — and while he usually works behind the scenes, he has played a major role in ensuring the unity and domination of the Shiites amid the turmoil after Saddam's fall.

But he has also shunned a public role and he opposes an Iranian-style government that would give direct rule to clerics.

The reference to clerics in the agreement was designed to give people in the new alliance a level of comfort that there was a higher authority to resolve disputes, Chalabi said.

In fact, most of the provisions in the agreement appear designed to limit the power of the prime minister.

The largest group within the Iraqi National Alliance, followers of radical cleric Muqtada al-Sadr, want to scale back the powers al-Maliki has built up during his premiership.

Those familiar with the meetings said many of the conditions came from the Sadrists, who were deeply unhappy with al-Maliki, who ordered a U.S.-Iraqi crackdown on Shiite militias in 2008.

"We are trying to avoid the mistakes of the past that led to the collapse of the former coalition and that made some people make unilateral decisions regarding the country," explained Ameer Taher al-Kinani, a Sadrist official, in an apparent reference to al-Maliki.

The provisions require the prime minister to consult on all decisions with members of the alliance and prohibit him from trying to form his own electoral list. Policy issues are also to be determined by committees from each of the Shiite blocs, further limiting the premier's role.

By putting in writing the role of the marjaiyah, the agreement also sets up a higher authority to the prime minister.